5-(piperidine-4-spiro) oxazolidin-2-ones

ABSTRACT

5 - PIPERIDINE - 4 - SPIRO)-OXAZOLIDIN - 2-ONES OF THE FORMULA:   3-R3,4-R2,8-R1-1-OXA-3,8-DIAZASPIRO(4.5)DECAN-2-ONE   IN WHICH: R1 IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, LOWER-ALKYL, PHENYLLOWER-ALKYL AND BENZOYLLOWER-ALKYL, R2 IS AMEMBER SELECTED FROM THE GROUP CONSISTING OF LOWER-ALKYL, PHENYL AND PHENYLLOWER-ALKYL AND R3 IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, LOWER-ALKYL, LOWER-ALKENYL, LOWER-ALKYNYL; LOWER-ALKANOYL, PHENYLLOWER-ALKYL AND BENZOYL, AND THE SALTS THEREOF, HAVE ANTIFIBRILLATING AND ANTIARYTHMIC PROPERTIES.

Jan- 12, 1971 J. G. A. MAILLARD 3,555,033

A 5f(PIPERIDINE4-SPIRO) OXAZOLIDIN-B-ONES Filed Aug. 21. 1967 o-Co. R1--N (I) CH-N-Ra OH CGHS-CHZ--N N (1I) CH--NHZ UnitedStates Patent O W 3,555,033 -(PIPERIDINE-4-SPIRO) OXAZOLIDIN-Z-ONES Jacques Georges Albert Maillard, Paris, France, assignor to Laboratoires Jacques Logeais, Issy-les-Moulineaux, France, a French body corporate Filed Aug. 21, 1967, Ser. No. 661,896 Claims priority, application Great Britain, Aug. 22, 1966, 37,477/ 66 Int. Cl. C07d 29/26 U.S. Cl. 260-294.3 6 Claims ABSTRACT OF THE DISCLOSURE 5 piperidine 4 spiro)oxazolidin 2-ones of the formula:

O-C O Ri-N i oH-N-R3 The present invention is concerned with novel compounds: 5 piperidine 4 spiro) oxazolidin 2-ones of general Formula I illustrated in FIG. 1 of the accompanying drawing, in which:

R1 is hydrogen, a lower-alkyl, plenyllower-alkyl or benzoyllower-alkyl group,

R2 is a lower-alkyl, phenyl or phenyllower-alkyl group,

and

R3 is hydrogen, a lower-alkyl, lower-alkynyl, lower-alkanoyl, phenylower-alkyl or benzoyl group,

and the pharmaceutically acceptable acid addition salts thereof |Preferably, the above-delined alkyl, alkenyl, Ealkynyl and alkanoyl groups are lower groups containing 1 6 carbon atoms. By aryl, laralkyl, aroyl and Iaroylalkyl groups are also meant, conventionally, anuclearly substituted groups of this type, particularly with halogen, alkyl, hydroxy, alkoxy, amino and alkylamino substituents. Preferably, the aryl and aroyl moieties of such groups are phenyl and benzoyl groups, respectively.

Compounds (I) exhibit useful therapeutic properties.

' The invention has also for its object a process for the preparation of compounds (I) which is illustrated in FIG. 2. This process, starting from the cyanohydrin (II) of 1-benzyl-piperidin-4-one, includes steps (a) through (g), steps (e) through (g) being involved only in the prep-aration of some of compounds (I).

This process comprises reacting 1benzyl4cyano4 hydroxy piperidine, whose hydroxyl group is protected by 3,555,033 Patented Jan. 12, 1971 ICC addition onto the dihydropyran, with an organomagnesium halide of formula RzMgHal, R2 having the above defined meaning and IHal being halogen, hydrolyzing the resulting magnesium derivative and hydrogenating the hydrolysis product, thereby obtaining a 1-benzyl-4-hydroxy-4-aminomethy1 piperidine substituted with group R2 on the methyl group, reacting this amine with a carbonyl derivative consisting of a carbonio diester, urea, urethane or phosgene, thereby obtaining a compound (In) of formula:

O O O C sHsr- C Hz-N: i

ICH-NH and introducing in any desired order, in said compound (Ia), substituent R3, when the latter is other than hydrogen, Iby reaction lwith a compound R3-X after replacement of the hydrogen to be substituted with an alkali metal, and substituent R1, when the latter is other than a benzyl group, by hydrogenation followed, eventually, by reaction with a compound R1X, X being halogen or a tosyl group.

The various steps of the process and the preferred procedures for carrying out such steps will be examined below in further detail.

Step (a).-For subsequent reactions, the OH grouping of cyanohydrin (II) is protected by addition in acidic medium onto the dihydropyran, leading to the dihydropyran ether of cyanohydrin (III).

Steps (b) and (ch-addition of an organomagnesium compound R2MgHal onto the nitrile group of derivative (III) leads to a complex which is not isolated and rthe hydrolysis of which, followed by hydrogenation by catalytic means or using lithium aluminum hydride in anhydrous neutral solvent) and then by hot treatment IWith excess -aqueous HCI, gives hydroxyl'ated amine (1V).

Step (d).-Ring closure of hydroxylated amine (IV) into derivative (la) is eiected with a carbonyl derivative COYZ which may be a carbonio diester, urea or urethane, in the presence of an alkali metal alkoxide such as sodium alkoxide, or phosgene in the presence of ya base which Ymay consist of excess amine. This step results ultimately in the production of derivatives (Im) forming a sub-group of the compound (I) family and wherein R1 is the benzyl group and R3 is hydrogen. To produce compounds (I) wherein R1 and/ or R3 have another meaning, one or more of the following steps are used:

Step (e).-Derivative (la) is transformed into (Ib), R3 having the above-mentioned meanings other than hydrogen, by means of a halide or a tosylate R3X reacting with a derivative of (la) wherein an alkali metal (generally, sodium) in a neutral solvent is substituted for hydrogen. This results in the production of derivatives (Ib), another sub-group of the compound (I) family and wherein R1 is the benzyl group and R3 is other than hydrogen.

Step (f).-Hydrogenolysis, in the presence of a palladium catalyst, of derivatives (la) and (Ib) leads to derivatives (Ic) and (Id), respectively, which are two further sub-groups of the compound (I) family and in which R1 is hydrogen and R3 is hydrogen or has any meaning, other than hydrogen, selected from those assigned above to R3, respectively.

Step (g).-Derivatives (lc) and (ld) may be substituted, on the piperidine nucleus nitrogen, with a RIX (halide or tosylate) derivative, according to the usual techniques for the substitution of secondary amines, R1 having the above-mentioned meanings other than hydrogen. In this manner, there are obtained derivatives (Ie) and (I), respectively. Derivative (Ie) is a last sub-group of the compound (I) family wherein R3 is hydrogen and wherein, in contrast, R1 is not hydrogen.

Finally, it should be noted that step (e) may be applied to compounds (Ic) and (Ie) to result in compounds (Id) and (l), respectively.

The following examples are given for the purpose of illustrating the invention:

EXAMPLE l.-5-( l-BENZYL-PIPERIDINE-4- SPIRO -4-ETHYL-OXAZOLIDIN-2-ONE (Compound (Ia), R2=C2H5) Step (a).-(1) In a 100 cc. flask, there are introduced 8 g. of 1-benzyl-4-cyano-4-hydroxy-piperidine (II) hydrochloride and 16 cc. of anhydrous dimethylsulfoxide. After dissolution, there are added 64 cc. of anhydrous dihydropyran and 36 cc. of 4 N hydrochloric acid in ether. The mixture is maintained 24 hours in an oil bath at 60 C. After cooling, the resulting crystals are suction filtered, and are then washed, with extended stirring, with anhydrous ethyl acetate. The suction filtered and dried product weighs 7.5 `g. (yield 70.7%) Inst. M.P.=195 C.

Analysis-Calw. (percent): Cl, 10.53; C, 64.17; H, 7.48. Found (percent): Cl, 10.63; C, 64.14; H, 7.55.

(2) Preparation of 1-benzyl-4-cyano 4 (tetrahydropyran-2-yl-oxy)-piperidine base (III): 50 mg. (0.15 mol) of 1-benzyl-4-cyano 4 (tetrahydropyran 2 yloxy)piperidne hydrochloride are stirred with 1,000 cc. of Water, 100 cc. of 2 N sodium hydroxide and 300 cc. of ether until disappearance of the solid. The decanted aqueous phase is extracted three times with ether. The ether extracts are dried over Drierite and are brought to dryness in vacuo. The remaining base is a colourless oil having a molecular weight (found) of 297 (theory 300.39). Quantitative yield.

Step (M -Preparation of 1-benzyl 4 (tetrahydropyran-2-yl-oXy)-4( l-imino-propyl)-piperidine.

In a four-necked 1 litre ask provided with reflux condenser, thermometer, stirrer and dropping funnel there are reacted 10.8 g. of magnesium turnings (0.45 atom) and 53.4 g. of ethyl bromide in 150 cc. of anhydrous ether. The 1-benzyl-4-cyano 4 (tetrahydropyran-2-yloxy)piperidine dissolved in 200 cc. of anhydrous ether iS then added with stirring, over 10 minutes, at 0-5" C. An oily phase precipitates rapidly. Stirring is continued for a further 2 hours, at 0 C., and the mixture is left standing overnight at room temperature. The magnesium compound is hydrolyzed by addition of 300 g. of crushed ice and 120 g. of ClNH4. Some solid impurities are filtered off, the ether phase is decanted, and the aqueous phase is extracted with 3 100 cc. of ether. The combined ether phases are dried over Drierite Step (c).-Reduction of the imine function of the compound obtained under (b), for the purpose of producing compound (IV). The ether solution is introduced in a flask containing 9.9 g. lithium aluminum hydride (8 times the theoretical amount) and 50 cc. of ether. The reaction mixture is refluxed for 2 hours, and is then hydrolyzed with cc. of isopropanol, followed by 15 cc. of concentrated NaCl solution. LiOH and A1203 are suction filtered and washed with ether. The solution is dried over MgSO4 and to it is then added excess HC1 in ether solution. The precipitated hydrochloride is suction filtered and is then boiled with normal HC1 and subsequently evaporated to dryness. It is used without further purification for the reaction with phosgene.

(0.146 mol calculated as pure product) is introduced in a flask together with 300 cc. of toluene, 500 cc. of water and 72 g. (1.28 mol) of potassium hydroxide. After cooling to 0 C., there are introduced, over 20 minutes, 219 g. of toluene solution that is washed until neutral. The filtered solid is dissolved in CHC13. The chloroform and toluene solutions are combined and are brought to dryness under reduced pressure. The solid is taken up into ethyl acetate and is extracted with ice cold' 2 N hydrochloric acid. The hydrochloric acid solution is then made alkaline and is extracted with CHC13. The chloroform solution is distilled to dryness, the residue is recrystallized from 210 cc. of CC14 and then from 1,100 cc. of a 6:4 water-methanol mixture. There are obtained 10.5 g. of this product. M.P.=170-l71 C. .M.W.: calculated: 274.37. Found: 273.9, 274.3.

Analysis-Calci (percent): C, 70.103; Found (percent): C, 69.24; H, 8.16.

EXAMPLE 2.-5( 1-BENZYL-PIPERIDINE-4-SPIRO 3,4-DIETHYL-OXAZOLIDINE-Z-ONE Step (e).-In a flask there are dispersed, with vigorous stirring, 0.402 g. (0.0174 at. g.) of sodium in cc. of boiling toluene. There are added 4.8 g. (0.0174 mol) of 5( l-benzyl-piperidine 4spiro)-4-ethyl-oxazolidin-Z-one; refluxing and stirring are maintained until the sodium has disappeared (4 hours). After distilling to dryness in vacuo, there are added 75 cc. of anhydrous dimethyl formamide and 3.7 g. (a 5% excess) of ethyl p-toluene sulfonate. The mixture is reuxed with stirring for 2 hours, and is then distilled to dryness in vacuo. The residue is taken up with benzene and the insoluble sodium p-toluene sulfonate is filtered off. The benzene is distilled to dryness. The oil is dissolved in 2 N HC1, is made alkaline, and is extracted with cyclohexane. The cyclohexane solution is washed 6 times with water to remove the dimethylformamide, it is dried over MgSO4 and hydrochloric acid in ether is then added to it. After suction-filtering and drying, the hydrochloride is crystallized twice from 2- propanol. Inst. M.P.=227 C. (dec.). Yield|=50%, 3 g.

AnaIyss.-Calcd. (percent): Cl. 10.46. Found (percent): Cl. 10.57-10.59.

EXAM PLE 3 .-5- PIPERIDINE-4-SPIRO -4-ETHYL- OXAZOLIDIN-Z-ONE (Compound (Ic) R2=C2H5) In a 500 cc. flask there are introduced 200 cc. of anhydrous ethanol; palladium at 5% over charcoal (l g.), and 3.6 g. of 5 (1 benzyl-piperidyl 4 Spiro) 4-ethyl-oxazolidin-Z-one. The mixture is hydrogenated at atmospheric pressure, with stirring. The theoretical amount of hydrogen is taken up in 21/2 hours. The catalyst is filtered olf and the solution is brought to dryness under reduced pressure. The solid residue is dissolved by boiling in cc. of anhydrous ethyl acetate. After 16 hours in the refrigerator, 2 g. of crystals are obtained by suctionfiltering (yield 82%). Tube M.P.=172-174 C.

Analysis: Calcd. (M.W.): 184.24. Found (M.W.): 186.70.

EXAMPLE 4.-5-( 1-ETHYL-PIPERIDINE-4-SPIRO 4-ETHYL-OXAZOLIDINE-2-ONE Step (g).-1.85 g. (0.01 mol) of 5-(piperidine-4-spiro) 4-ethyl-oxazo1idin-2-one are dissolved in 20 m1. of anhydrous dimethyl formamide and are heated with 1.1 g. (0.01 mol) of ethyl bromide, in a closed flask, during 8 hours, at 50 C.

After evaporation of the solvent under reduced pressure, the residue is taken up with 30 ml isopropyl oxide and 30 ml. of 0.5 N HC1.

The decanted aqueous phase is evaporated to dryness under reduced pressure and the residue, consisting of the hydrochloride of the desired product, is recrystallized from ethanol.

t Analyss.-Calcd. (percent): C, 53.1; H, 8.05; Cl, 14.30. Found (percent): C, 53.0; H, 7.80; Cl, 14.40.

(Compound (Ia) R2J=C6H5) Step (by- Using the same conditions as described in Example 1, 3.65 g. (0.15 atom) of magnesium and 25.85 g. (0.165 mol) of bromobenzene are reacted in 70 ml. of anhydrous ether, and 0.05 mol of 1-benzy1-4-cyano-4- (tetrahydropyran-Z-yl-oxy)-piperidine dissolved in 100 ml. of anhydrous ether are then added over 35 minutes, with stirring, at C. Stirring is continued for a further 20 minutes at 0 C., and the mixture is then hydrolyzed by addition of 100 g. of ice and 50 ml. of saturated NHrCl solution. The separated aqueous phase is extracted with ether, and the combined ether phases are dried over Drieritef Step (c).-The above ether solution is refluxed for 2 hours with 3.3 g. of LiA1H4. The reaction mixture is hydrolyzed by addition of 25 ml. of isopropanol and 25 ml. of saturated NaCl solution, the precipitated alumina is filtered off and the ether phase is extracted with 2 N HCl. The hydrochloric solution is made alkaline with excess sodium hydroxide and the oily base is extracted with ether. After drying over Drierite, this ether solution is treated with anhydrous HC1 solution in ether. After suction-filtering and drying the precipitate, there are obtained 16.3 g. (88%) of crude hydrochloride that are crystallized from 1-10 ml. of t-butanol and subsequently puried by boiling in isopropanol (IV hydrochloride R2: CeH) Step (d).-6.65 =g. (0.018 mol) of the above hydrochloride -are introduced into a flask together with 40 ml. of toluene, 50 ml. of water -and 8 g. (0.144 mol) of potassium hydroxide. 27 g. (0.054 mol) of phosgene in toluene solution are added with stirring, over 30 minutes, at 0 C. The resulting solid is ltered off and washed with chloroform. The aqueous phase is extracted with chloroin Example 3, together with 30 ml. of anhydrous dimethyl formamide and 1.99 g. (0.01 mol) of 3-phenyl-l-bromopropane, and the reaction mixture is then heated 13 hours at 5 0 C. After distillation of the solvent under reduced pressure, the residue is taken up with 30 ml. of isopropyl oxide and 30 m1. of 0.5 N HC1. The decanted aqueous phase is made alkaline with excess 2 N sodium hydroxide and the base is extracted with ethyl acetate. =Evaporation of the solvent leaves a solid which is recrystallized from 30 ml. of 1:1 methanol-water. There are obtained 1.6 g (53%) of needles. M P.=137-138 C.

Analyss. Calcd.: M.W. 302.4; C, 71.48%; H, 8.66%. Found: M.W., 303; C, 71.22%; H, 8.67%.

(Compound (Ie) R1= F- R2=C2H5) Step (g).-l.85 g. (0.01 mol) of derivative (Ic) (R2=C2H5) in 30 ml. of anhydrous dimethylformamide are heated with 2.05 g. (0.01 mol) of 4-p-lluorophenyl-4- oxo-l-chloro-butane and 500 mg. of sodium iodide, for 6 hours, at C. The residue obtained after evaporating to dryness under reduced pressure is taken up with 30 ml. of isopropyl oxide and 30 ml. of normal HCl. The aqueous phase is separated, and is made alkaline with excess sodium hydroxide, and is then extracted with ethyl acetate. After evaporation of the solvent, the residue is crystallized from a 1:1 methanol-water mixture, and then from isopropanol. There are obtained 1 g. (28.7%) of crystals. M.P.=151-l55 C. (dec.).

Analysis.-Calcd.: M.W. 384.4; N, 8.04%. Found: M.W., 384.10 (acidimetric determination); N, 8.03%.

`Operating as in Example 1, but substituting the ethyl bromide, in step (b), with methyl iodide, p-methoxyphenyl bromide, n-butyl bromide, p-chlorophenyl bromide and p-dimethylaminophenyl bromide, there are obtained, respectively, compounds (la) of Examples 8-12 listed in the following Table I:

TABLE I.-COMPOUNDS (Ia) -C O-CHz-CHz-CHZ Compound R2 M.P. C.

8..-. 5-(1-benzyl-piperidine-L-spiro)-4-methyl-oxazolidin-2-one CH3 159-160 9 -(l-benzyl-piperidine-l-spiro)-4-p-methoxyphenyl-oxazolidin-2-one p-CH3OC5H4 164 10. 5-(1-benzyl-piperidine-4-spiro)-4-n-butyl-oxazolidin-2-one n-C4H9 1 271 11 5-(1-benzyl-plperidine-l-spiro)-4-p-ehlorophenyl-oxazolidin-2-one p-Cl-CGH4 172-173 l Hydroehloride.

form and the chloroform solutions are combined with the 50 Step (g).-In a 50 cc. ask, there are introduced 1.85 g. (0.01 mol) of derivative (Ic) (R2=C2H5) described When operating as in Example 2, but substituting the ethyl p-toluene sulfonate, in step (e), by methyl, n-butyl, allyl and propargyl p-toluene sulfonate or a corresponding halide, there are obtained, respectively, compounds (1b) of Examples 1346.

Similarly, when applying to the compound of Example 5 step (e) of Example 2 as such or substituting the ethyl p-toluene sulfonate of this step with phenethyl, phenylpropyl, acetyl and benzoyl p-toluene sulfonate or halide, there are obtained, respectively, the compounds (Ib) of Examples 17-21.

The compounds (Ib) thus prepared are listed in Table II below in which, for purposes of brevity, the 1benzyl piperidine-4-spiro group is represented by the symbol B.P.S.

TABLE II.-COMPOUNDS (Ib) Compound R2 R3 M.P. C.

13 5-(B.P.S )-S-methyl--ethyl-oxazolidin-Z-one- CH3 1222 14 5-(B.P.S.)-3-n-butyl-4-ethyl-oxazolidin-2-one 02H5 n-C4Hu 15 5-(B P.S )-B-allyl-l-ethyl-oxazolidin-2-one 02H5 CH2CH=CH2 2236 16 5-(B.P.S )-3-propargyl--ethyl-oxazolidin-Z-one 02H5 CHQCECH 105-106 17 5-(B.P.S.)-3-ethyl-4-phenyl-oxazolidin-2-one CH5 02H5 104-142 18 5- (B .P .S 3-a-phenethyl-4-phenyl-oxazolidin-Q-one 05H5 CH5CH2CH2 19.. 5 (B .P S -3-a-phenylpropyl-4-phenyl-oxaz olidin-2-o 05H5 CaH5(CH2) 3 120-121 20 5-(B P.S )-4-phenyl-B-acetyl-oxazolidn-Z-one 00H5 CHBCO 2 200 21 5-(B.P.S.)-4-ethyl-3-benzoyl-oxazolidin-2-one CaHi CHCO 98-100 1 Decomposition (hydrochloride).

a Hydrechloride.

EXAMPLE 23 .-5 PIPERIDINE-4-SPIRO) 3 ,4-DIETHYL-OXAZOLIDIN-Z-ONE (Compound (Id) R2=R3=C2H5) Step (f).--17 g. (0.056 mol) of 5-(1-benzyl-piperidine-4-spiro) 3,4-diethyl-oxazolidin-Z-one hydrochloride are converted into the free base by addition of aqueous sodium hydroxide. After ether extraction and evaporation of the solvent, the base is obtained in the form of an oil which is hydrogenated under normal pressure and temperature, in 200 ml. of ethanol, in the presence of palladiumover-charcoal. Yield: 91%.

AnaIysis.-Calcd.: C, 62.22%; H, 9.50%; M.W. (acidimetric determination) 212.3. Found: C, 61.57%; H, 9.95%; M.W. (acidimetric determination) 212.2.

EXAM PLE 24.-5 PIPERIDINE-4-SPIRO 3-ETHYL 4-PI-LENYL- OXAZOLIDIN-2- ONE Step (f).-8 g. of 5(1-benzyl-piperidine-4-spiro)-3- ethyl-4-phenyl-oxazolidin-Z-one are hydrogenated in 100 ml. of ethanol in the presence of palladium-over-charcoal, at 50 C., at ordinary pressure. The oily base is obtained by evaporation of the solvent. (Yield 100%).

Analysis.-Calcd.: M.W. (acidimetric determination) 260.3. Found: M.W. (acidimetric determination) 267.

EXAMPLE .-5 l--PHENYLETHYL-PIPERI- DIN'E-4-SPIRO -4-PHENYL-OXAZOLIDLN -2-ONE (Compound RIICGH5CH2CH2 R2:C5H5) Step (g).-5.5 g. (0.0236 mol) of S-(piperidine-4- spiro)-4-phenyl-oxazolidin-Z-one are heated with 30.8 g. (0.165 mol) of 1-phenyl-2-bromo-ethane, as in Example 6. i

The base released by alkalinization precipitates as a solid which is recrystallized from 250 ml. of isopropanol.

Weight, 3.6 g. (45.5%). M.P.=234 C. (inst.).

Analysis.-Calcd. (percent): C, 75.19; H, 6.91; N,

8.36. Found (percent): C, 75.03; H, 7.33; N, 8.34.

EXAMPLE 26.-5( l-fy-PHENYLPROPYL-PIPERI- DINE-4-SPIRO -4-PHENYL-OXAZOLIDIN 2-ONE (Compound R1=C6H5CH2CH2CH2 R2ZCGH5) Step (g).-4.7 g. (0.02 mol) of 5-(piperidine4spiro) 4-phenyl-oxazolidin-2-one are heated with 16 g. (0.08 mol) of 1phenyl-3bromopropane, as in the preceding example.

The base is obtained as a solid which is recrystallized from acetonitrile. Weight: 4.2 g. (59%). M.P.=163 4 C.

Analyss.-Calcd. (percent): C, 75.39; H, 7.48; N, 8.0. Found (percent): C, 75.37; H, 7.50; N, 8.10.

IEXAMPLE 27 .-5 l- (4p-FLUOROPHENYL-4OXO BUTYL) -PIPERIDINE-4-SPIRO] -4-PHENYL- OXAZOLIDIN-Z-ONE Step (g).-8.13 g. (0.035 mol) of 5-(piperidine-4- spiro)-4-phenyl-oxazolidin-2-one are heated with 14 g. (0.070 mol) of 3-p-uorobenzoyl-l-chloro-propane, in a boiling water-bath, until neutral (l1/2hrs). The mixture is taken up with m1. of ether, the crystals are suction filtered, dissolved in boiling Water and decolorized over charcoal. The base is released by alkalinization of the filtrate and is extracted with chloroform. After evaporation of the solvent, the residue is taken up with methyl ethyl ketone followed by ethyl acetate, and is converted into lhydrochloride by addition of a solution of HCl in ether. After further decolorization of the hydrochloride with charcoal, the base is again obtained by alkalinization and is solidiiied by trituration with methalyl, and is then recrystallized from ethyl acetate. Weight: 3.3 g. (23%). M.P. 159-61 C.

Analysis.-Calcd.: N, 7.07%; M.W. acidimetric determination) 396.4. Found; N, 7.12%; M.W. (acidimetric determination) 396.

The following compounds (Ie) were prepared in the same manner as in Examples 25-27 (step (g)):

(Compound R1`=CH3(CH2)5 R2=C6H5) M.P.=168170 C. Analyss.-Calcd. (percent): C, 72.11; H, 8.92; N, 8.85. Found (percent): C, 72.08; H, 8.95; N, 8.95.

EXAMPLE 29.--5 l-PHENACYL-PIPERIDINiE-4- SPERO -4-ETHYL-OXAZOLI-DINE-2-ONE M.P. 178-180" C.

Analyss.-Calcd. (percent): C, 67.52; H, 7.33; N, 9.27. Found (percent): C, 67.67; H, 7.49; N, 9.14.

EXAMPLE 3 0.-5[ l- 3-PHENYL-3-OXO-PROPYL) PIPERIDINE-4-SPIRO] -4-ETHYL- OXAZOLIDIN-Z-ONE Analyss.-Calcd. (percent): C, 68.33; H, 7.65; N, 8.85. Found (percent): C, 68.35; H, 7.75; N, 8.90.

The Examples 31-33 below relate to the preparation of compounds (I).

EXAMPLE 3 1.--5( l--PHENYLETHYL-PIPERI- DINE-4-SPIRO -3 ,4-DIETHYL- OXAZOLIDIN-Z-ONE Step (g).-4.2 g. (0.02 mol) of 5-(piperidine-4-spiro) 3,4-diethyl-oxazolidin-2-one and 14 g. (0.08 mol) of 1- phenyl-2-bromo-ethane are heated during 5 hours in a. boiling Water-bath. The mixture sets rapidly to a mass. After cooling, the crystalline solid is diluted with ether and is suction filtered. It is dissolved in hot water and is decolorized over active charcoal. The solution is made alkaline with excess sodium hydroxide: the oily base is extracted with cyclohexane. After evaporation of the solvent, the residue is taken up with a small excess of normal HC1 at 40 C.: the resulting hydrochloride dissolves, and then recrystallizes. Weight: 5.85 g. (83%). M.P. 202 C. (inst.).

Analysis.-Calcd. (percent): C, 64.66; H, 8.28; Cl, 10.04. Found (percent): C, 64.82; H, 8.33; Cl, 10.08.

EXAMPLE 3 2.-5( l-fy-PHENYLPROPYL-PIPERI- lDINE-4-SPIRO -3 ,4-DIETHYL OXAZOLIDI'N-Z-ONE Step (g).-4.25 g. (0.02 mol) of 5-(piperidine-4- Spiro)-3,4-diethyl-oxazolidin-Z-one are heated with 16 g. (0.08 mol) of 1-phenyl-3-bromo-propane, as in the preceding example.

The extracted has@ .iS Converted into hydrochloride 9 which is recrystallized from dioxan and then from water. Weight: 3.1` g. (42%). M.P.=152 C. (inst).

Analyss.-Calcd. (percent): C, 65.46; H, 8.51; N, 7.64; Cl, 9.66. Found (percent): C, `65.41; H, 8.71; N, 7.64; Cl, 9.76.

EXAMPLE 3 3 .-5 l- 4-p-FLUOROPHENYL-4-OXO- BUTYL) -PIPERIDINE 4 SPIRO'] -3 ,4-DIETHYL- OXAZOLIDIN-Z-ONE (compound (I) R1= F- @-0 owcHQoHzcHz Step (g).-4.25 g. (0.020 mol) of 5-(piperidine-4-spiro)3,4-diethyl-oxazolidin-2-one are treated in the hot with 8 g. (0.040 mol) of S-p-uorobenzoyl-l-chloro-propane, as in the preceding example. Y

The hydrochloride obtained by addition of a solution of HC1 in ether is crystallized from isopropanol. Weight: 2.45 g. (30%). M.P. 184 C.

Analysis-Calci (percent): N, 6.78; Cl, 8.58. Found (percent): N, 6.78; Cl, 8.69.

As mentioned hereinbefore, the 5-(piperidine-4-spiro)- oxazolidin-Zj-ones of formula (I) exhibit usefulftherapeutic properties. They possess, particularly, anti-arhythmic and anti-brillating properties evidenced on the isolated heart fof mammalians or on the entire animal and confirmed in human clinics.

The evaluation of the refractory period of time Aduring which the myocardial tissue is no longer responsive to the action of an external electric stimulus was effected on isolated 'rabbit hearts perfused with a physiological solution at 37 C.

The introduction of the test materials in the perfusion liquid produces an extension of this resting period, Arepresenting a decrease of the potential appearance of extrasystoles. The results obtained are summarized in the following table:

Product of Percent extension of the refractory Example No.: period of time (on isolated heart) l 25% at a concentration of 5 'y/ml. 1 37% at a concentration of 25 'y/ml. 2 25% at a concentration of 5 y/ ml. 2 65% at a concentration of 25 q/ml. 5 55% at a concentration of 5 'y/ml. 6 53% at a concentration of 5 'y/ml. 7 100% at a concentration of 10 vy/ ml. 8 47% at a concentration of 10` 'y/ml. 9 40% at a concentration of 5 `fy/ml. 17 53% at a concentration of 5 y/ml. 23 38% at a concentration of 50 ^I/ml. 27 40% at a concentration of 5 ry/ ml. 31 70% at a concentration of 5 'y/rnl. 32 52% at a concentration of 5 'y/ ml. 33 70% at a concentration of l0 'y/ml.

On the other hand, heart brillations were produced in rat by injection of aconitine nitrate, by the I.V. route, at the dosage of 7 g. per animal.

The administration of anti-brillating materials, begun l hour prior to the acontine injection, insures protection of the animals. Thus:

2O mg./kg., by the intraveinous route, of the product of -Example 1, protect of the animals.

mg./ kg. per os, of the product of Example l, protect 25 of the animals.

10 mg./kg., by the intraveinous route, of the product of Example 6, protect 65 of the animals,

I claim:

1,. A member selected from the group consisting of the 5-(piperidine-4-spiro)-oxazolidin-2-ones of the general formula:

in which R1 is a member selected from the group consisting of hydrogen, lower-alkyl, phenyllower-alkyl and benzoyllower-alkyl,

R2 is a member selected from the group consisting of lower-alkyl, phenyl and lower-alkyl phenyl, and

R3 is a member selected from the group consisting of hydrogen, lower-alkyl, lower-alkenyl, lower-alkynyl, lower-alkanoyl, phenyllower-alkyl and benzoyl, and the pharmaceutically acceptable acid addition salts thereof.

2. 5(1-7-phenylpropyl-piperidine 4 spiro)4ethyloxazolidin-2-one and the pharmaceutically acceptable acid addition salts thereof.

3. 5-[1-(4-p-fluorophenyl 4 oxobutyl)piperidine-4 Spiro]-4-ethyl-oxazolidin-2-one and the pharmaceutically acceptable acid addition salts thereof.

4. 5[1(4-pfluorophenyl 4 oxo-butyl)piperidine4 spiro]-4-phenyl-oxazolidin-2-one and the pharmaceutically acceptable acid addition salts thereof.

S. 5(l--phenylethyl-piperidine 4 spiro) 3,4 diethyl-oxazolidin-Z-one and the pharmaceutically acceptable acid addition salts thereof.

6. 5-(1-fy-phenylpropyl-piperidine 4 spiro)3,4-diethyl-oxazolidin-Z-one and the pharmaceutically acceptable acid addition salts thereof.

References Cited UNITED STATES PATENTS 3,399,192 8/1968 Regnier et al 260-240 OTHER REFERENCES Parham et al., I, Am. Chem. Soc., 70, 4187-9 (1948).

HENRY R. JILES, Primary Examiner G. THOMAS TODD, Assistant Examiner U.S. C1. X.R. 

